21425463959657 has 2 divisors, whose sum is σ = 21425463959658. Its totient is φ = 21425463959656.

The previous prime is 21425463959609. The next prime is 21425463959729. The reversal of 21425463959657 is 75695936452412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11755702538281 + 9669761421376 = 3428659^2 + 3109624^2 .

It is a cyclic number.

It is not a de Polignac number, because 21425463959657 - 2⁶ = 21425463959593 is a prime.

It is a super-2 number, since 2×21425463959657² (a number of 27 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21425463959957) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10712731979828 + 10712731979829.

It is an arithmetic number, because the mean of its divisors is an integer number (10712731979829).

Almost surely, 2^{21425463959657} is an apocalyptic number.

It is an amenable number.

21425463959657 is a deficient number, since it is larger than the sum of its proper divisors (1).

21425463959657 is an equidigital number, since it uses as much as digits as its factorization.

21425463959657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 489888000, while the sum is 68.

The spelling of 21425463959657 in words is "twenty-one trillion, four hundred twenty-five billion, four hundred sixty-three million, nine hundred fifty-nine thousand, six hundred fifty-seven".